Software product line engineering is an established methodology for fast and effective development of software-intensive systems and services. To reap maximum benefits from the methodology, businesses typically need to implement coordinated changes in development methodologies, tools, product architectures, organizational designs, and business models. Product lines are developed in complex international software ecosystems, but there is no coordinated set of international standards for defining and leveraging the methodology. As a result, ecosystems cannot adopt standardized methods and tools for developing product lines, tool vendors face difficulties in developing tools to enable product line engineering, and universities cannot effectively set up product line engineering courses because an internationally accepted curriculum is missing. The International Organization for Standardization has initiated several projects to create a set of international standards for software product line engineering. Practitioners, researchers, and other stakeholders can contribute to these projects through their national standards bodies. This paper discusses the projects and future directions for product line standardization.